Role of Major Forest Biomes in Climate Change Mitigation …
493
The edge effects make the edge species to become more vulnerable to biotic and
abiotic perturbations (Laurance et al. 2007; Pravalie 2018). Further, altered environmental conditions results in high temperature, wind, vapour pressure deficit and
availability of light, nutrients, and other resources (Matlack 1993; Reinmann and
Hutyra 2017). Habitat fragmentation limits nutrient flow and connectivity and interaction of species across two or more ecosystems (Billings and Gaydess 2008; Auffret
et al. 2015; Pravalie 2018).According to Jenkins (1992), if the habitat fragmentation
rates are very high, terrestrial and protected areas are akin to isolated “ecological
islands” that are surrounded by “oceans” of altered habitats leading to gradual loss
of biodiversity and augmenting species extinctions which destabilizes the ecosystem
integrity (Myers 1979; Jenkins 1992; Kappelle et al. 1999). However, the effects
depend on several factors such as size of the forest fragments, species characteristics, species interactions and nature of the surrounding habitat (Gibson et al. 2013;
Estrada et al. 2017; Pravalie 2018). As a result of loss in home ranges of top carnivores due to forest fragmentation, there occurs a total collapse of the entire trophic
level, severely impairing ecosystem functioning (Dobson et al. 2006; Mooney et al.
2009). Fragmented patches of forests tend to become drier and are susceptible to
forest fires (Corlett 2018). Thus, habitat fragmentation is clearly an important factor
that not only advances climate change via several mechanisms, but also impacts the
ecosystem functioning and services.
3.3 Land-Use Change
Land-use change is another one of the important factors for climate change and is
expected to increase in the coming future, due to increasing demands for agricultural
and biofuel production, migration of human populations, etc. (Corlett 2018). Landuse change virtually affects almost all kinds of ecosystem services, especially the
regulating and provisioning services (Abrams et al. 2018). Land-use changes have
already altered several ecosystem services like nutrient cycling, water regulation,
timber production, carbon sequestration, etc. (Bhattarai 2017). Land-use change to
agricultural or urban systems drives many species to extinction, at least regionally
(Pravalie 2018). It also results in the loss of massive amounts of carbon that was
previously accrued in different carbon pools for a long time (Naudts et al. 2016;
Pravalie 2018). Studies envisaged that due to land use changes, forest area has been
reduced by one-third and with concommitment emission of about 146 Pg C back to
the atmosphere, since 1850 (Williams 2006; Reinmann and Hutyra 2017). Moreover,
it has led to widespread habitat fragmentation due to which 20% of the world’s forest
cover now lies within 100 m of a forest’s edge (Haddad et al. 2015; Reinmann and
Hutyra 2017). Land-use changes contribute to global climate change in two ways:
biogeochemical effects (such as the absorption and release of greenhouse gases like
carbon dioxide) and biophysical effects (such as alterations in the surface energy
493
The edge effects make the edge species to become more vulnerable to biotic and
abiotic perturbations (Laurance et al. 2007; Pravalie 2018). Further, altered environmental conditions results in high temperature, wind, vapour pressure deficit and
availability of light, nutrients, and other resources (Matlack 1993; Reinmann and
Hutyra 2017). Habitat fragmentation limits nutrient flow and connectivity and interaction of species across two or more ecosystems (Billings and Gaydess 2008; Auffret
et al. 2015; Pravalie 2018).According to Jenkins (1992), if the habitat fragmentation
rates are very high, terrestrial and protected areas are akin to isolated “ecological
islands” that are surrounded by “oceans” of altered habitats leading to gradual loss
of biodiversity and augmenting species extinctions which destabilizes the ecosystem
integrity (Myers 1979; Jenkins 1992; Kappelle et al. 1999). However, the effects
depend on several factors such as size of the forest fragments, species characteristics, species interactions and nature of the surrounding habitat (Gibson et al. 2013;
Estrada et al. 2017; Pravalie 2018). As a result of loss in home ranges of top carnivores due to forest fragmentation, there occurs a total collapse of the entire trophic
level, severely impairing ecosystem functioning (Dobson et al. 2006; Mooney et al.
2009). Fragmented patches of forests tend to become drier and are susceptible to
forest fires (Corlett 2018). Thus, habitat fragmentation is clearly an important factor
that not only advances climate change via several mechanisms, but also impacts the
ecosystem functioning and services.
3.3 Land-Use Change
Land-use change is another one of the important factors for climate change and is
expected to increase in the coming future, due to increasing demands for agricultural
and biofuel production, migration of human populations, etc. (Corlett 2018). Landuse change virtually affects almost all kinds of ecosystem services, especially the
regulating and provisioning services (Abrams et al. 2018). Land-use changes have
already altered several ecosystem services like nutrient cycling, water regulation,
timber production, carbon sequestration, etc. (Bhattarai 2017). Land-use change to
agricultural or urban systems drives many species to extinction, at least regionally
(Pravalie 2018). It also results in the loss of massive amounts of carbon that was
previously accrued in different carbon pools for a long time (Naudts et al. 2016;
Pravalie 2018). Studies envisaged that due to land use changes, forest area has been
reduced by one-third and with concommitment emission of about 146 Pg C back to
the atmosphere, since 1850 (Williams 2006; Reinmann and Hutyra 2017). Moreover,
it has led to widespread habitat fragmentation due to which 20% of the world’s forest
cover now lies within 100 m of a forest’s edge (Haddad et al. 2015; Reinmann and
Hutyra 2017). Land-use changes contribute to global climate change in two ways:
biogeochemical effects (such as the absorption and release of greenhouse gases like
carbon dioxide) and biophysical effects (such as alterations in the surface energy